A.2 Computation example

A sample of 35 vessels of the same type and manufacture shall be taken at random in one or several batches so that the sample is as representative as possible of the production.

The following computational procedure is taken from the International Standard ISO 3951:1989, letter code J, AQL = 2.5, normal control, unknown standard deviation.

Compute the mean of the capacities of the vessels in the sample:

(A.1)

with .

Compute the standard deviation of the capacities of the vessels in the sample:

(A.2)

with .

Compute the specified upper limit , the sum of the capacity to be verified and of the maximum permissible error for this capacity.

Compute the specified lower limit , the difference between the capacity to be verified and the maximum permissible error for this capacity.